This invention relates to a method of manufacturing a stopper of the type which may be used, for example, as a cork stopper for a wine bottle.
Wine production has increased worldwide to a significant extent over the years. Traditionally wine bottles have been closed off with stoppers made from natural cork material. With the increase with wine production the demand for cork material has increased considerably. Good quality cork has increased in price considerably over the years due to the scarcity value attached to quality cork.
Various attempts have been made to overcome the shortage of quality cork material. For example, plastic stoppers and screw-cap stoppers have been developed which, in practice, operate at least as effectively as natural cork. However, there is a consumer resistance to plastic stoppers and certainly bottlers of quality wines and other beverages continue to prefer cork stoppers for their product. Another attempt to overcome the shortage of quality cork material has been to reconstitute a solid cork from comminuted lesser quality cork particles using an adhesive. Cork stoppers are then cut from the reconstituted material. These corks, however, have proved to be less than satisfactory since they often leak and tend to break up and can be difficult to extract from a bottle.
A further attempt to solve the problem of cork shortages and expense has been to coat lesser quality corks or reconstituted corks with a sealant, or to impregnate them with a silicone oil, as described in British patent no. GB 1,207,674. However, known sealants have, for one or other of the following reasons, proved to perform inadequately. Since a cork is often required to remain in situ and to provide an effective seal for a number of years, any deterioration in the sealant over time will tend to result in failure of the seal. The composition which seals the cork should also not contaminate the contents of the bottle in any way. The cost of the sealant should not be excessive and the sealant should not make insertion of the cork into the bottle or removal of the cork from the bottle too difficult. The sealant should also retain its flexibility over the intended life of the product and should not crack or break up on being removed from the bottle.